Pharmaco Photonics (DBA FAST Biomedical) proposes a PHASE IIB project to determine the safety and functionality of repeat administration of the FAST PV and mGFR Technology in both non-clinical and clinical studies. The long-term goal of this SBIR project is to test FAST's fluorescent based test in humans and commercializes this product for rapid detection and quantification of glomerular filtration rate (GFR) and plasma volume (PV) in patients with acute kidney injury (AKI) chronic kidney disease (CKD), and/or volume instability. AKI remains a vexing clinical problem resulting in unacceptably high patient mortality, development of CKD and enhanced progression to end stage renal disease. FAST has developed the FAST PV and mGFR Technology, a simple blood draw technique for direct measurement of GFR and PV. In CKD patients, the estimated GFR (eGFR) method for determining baseline GFR and following disease progression and response to therapy has proved to be a disappointment. Having a rapid point of care ability to measure GFR (mGFR) would greatly improve patient stratification, management and evaluation of therapies. The Test is intended as an adjunct to current methods utilized to assess renal function. This Test has been successfully tested under physiologic and AKI conditions in dogs and in increasing levels of CKD in humans. Based upon this success, FAST proposes to test the repeated administration of the FAST PV and mGFR Technology TM in repeat dose non-clinical studies (Phase IIB Specific Aim 1). Based on success of the non-clinical studies FAST proposes to test the repeated administration of the FAST PV and mGFR Technology TM in humans (Phase IIB Specific Aim 2) for determination of GFR and PV, under an FDA- Investigational Device Exemption (IDE) Pilot Human Trial (C). GFR and PV will be determined in sixteen (16) healthy volunteers receiving either a volume (8) or protein (8) challenge in order to evaluate the test's safety with rapid repeated doses, efficacy, and repeatability and quantify renal reserve. It will also be studied in an additional eight (8) volunteers of varying degrees of kidney function and compared to an iothalamate clearance with both repeated one week later. This will allow for the evaluation of safety and efficacy over the spectrum of GFRs seen in kidney disease, with repeat doses one week apart and compared to the present day standard. This FAST PV and mGFR Technology TM is of major clinical importance in AKI and CKD patients, especially in high risk patients where intense surveillance is necessary for early diagnosis, stratification by severity, and response to therapy. Furthermore, this new technology for rapid measurement of GFR will for the first time permit early dynamic assessment of kidney function in multiple animal models of human disease; thus expanding scientific knowledge regarding the role of kidney function during early disease onset. Finally, the ability to quantify and follow PV dynamically will greatly aid the critical care physician in many ICU patients.